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https://www.readbyqxmd.com/read/27922019/nanomechanical-motion-transduction-with-a-scalable-localized-gap-plasmon-architecture
#1
Brian J Roxworthy, Vladimir A Aksyuk
Plasmonic structures couple oscillating electromagnetic fields to conduction electrons in noble metals and thereby can confine optical-frequency excitations at nanometre scales. This confinement both facilitates miniaturization of nanophotonic devices and makes their response highly sensitive to mechanical motion. Mechanically coupled plasmonic devices thus hold great promise as building blocks for next-generation reconfigurable optics and metasurfaces. However, a flexible approach for accurately batch-fabricating high-performance plasmomechanical devices is currently lacking...
December 6, 2016: Nature Communications
https://www.readbyqxmd.com/read/27920491/interactive-navigation-guided-ophthalmic-plastic-surgery-navigation-enabling-of-telescopes-and-their-use-in-endoscopic-lacrimal-surgeries
#2
Mohammad Javed Ali, Swati Singh, Milind N Naik, Swathi Kaliki, Tarjani Vivek Dave
PURPOSE: The aims of this study were to report the preliminary experience of using telescopes, which were enabled for navigation guidance, and their utility in complex endoscopic lacrimal surgeries. METHODS: Navigation enabling of the telescope was achieved by using the AxiEM™ malleable neuronavigation shunt stylet. Image-guided dacryolocalization was performed in five patients using the intraoperative image-guided StealthStation™ system in the electromagnetic mode...
2016: Clinical Ophthalmology
https://www.readbyqxmd.com/read/27920433/polarization-conversion-when-focusing-cylindrically-polarized-vortex-beams
#3
Alexey P Porfirev, Andrey V Ustinov, Svetlana N Khonina
Currently, cylindrical beams with radial or azimuthal polarization are being used successfully for the optical manipulation of micro- and nano-particles as well as in microscopy, lithography, nonlinear optics, materials processing, and telecommunication applications. The creation of these laser beams is carried out using segmented polarizing plates, subwavelength gratings, interference, or light modulators. Here, we demonstrate the conversion of cylindrically polarized laser beams from a radial to an azimuthal polarization, or vice versa, by introducing a higher-order vortex phase singularity...
December 2016: Scientific Reports
https://www.readbyqxmd.com/read/27919300/a-randomised-placebo-controlled-trial-of-transcranial-pulsed-electromagnetic-fields-in-patients-with-multiple-chemical-sensitivity
#4
Marie Thi Dao Tran, Sine Skovbjerg, Lars Arendt-Nielsen, Karl Bang Christensen, Jesper Elberling
OBJECTIVE: To evaluate the efficacy of transcranially applied pulsed electromagnetic fields (PEMF) on functional impairments and symptom severity in multiple chemical sensitivity (MCS) patients. METHODS: The study was conducted as a nationwide trial in Denmark using a randomised, parallel-group, double-blind and placebo-controlled design. Sample size was estimated at 40 participants. Eligibility criteria were age 18-75 years and fulfilment of the MCS case criteria...
December 6, 2016: Acta Neuropsychiatrica
https://www.readbyqxmd.com/read/27918962/source-localization-of-epileptiform-discharges-in-juvenile-myoclonic-epilepsy-jme-using-magnetoencephalography-meg
#5
Veeranna Gadad, Sanjib Sinha, Narayanan Mariyappa, Ganne Chaithanya, Velmurugan Jayabal, Jitender Saini, Kandivel Thennarasu, Parthasarathy Satishchandra
OBJECTIVE: The purpose of this study is to localize the sources of epileptiform discharges (EDs), in juvenile myoclonic epilepsy (JME) using Magnetoencephalography (MEG), at three different time instances and analyze the propagation of EDs, from onset to offset, for inferring the cortical and subcortical region of involvement. METHODS: Twenty patients (age 23.5±6.3years old) with JME were recruited in this prospective study. MEG source analysis was performed on the independently collected EDs of each patient...
November 29, 2016: Epilepsy Research
https://www.readbyqxmd.com/read/27918416/a-touch-sensing-technique-using-the-effects-of-extremely-low-frequency-fields-on-the-human-body
#6
Hatem Elfekey, Hany Ayad Bastawrous, Shogo Okamoto
Touch sensing is a fundamental approach in human-to-machine interfaces, and is currently under widespread use. Many current applications use active touch sensing technologies. Passive touch sensing technologies are, however, more adequate to implement low power or energy harvesting touch sensing interfaces. This paper presents a passive touch sensing technique based on the fact that the human body is affected by the surrounding extremely low frequency (ELF) electromagnetic fields, such as those of AC power lines...
December 2, 2016: Sensors
https://www.readbyqxmd.com/read/27917886/dynamical-tuning-between-nearly-perfect-reflection-absorption-and-transmission-of-light-via-graphene-dielectric-structures
#7
Jacob Linder, Klaus Halterman
Exerting well-defined control over the reflection (R), absorption (A), and transmission (T) of electromagnetic waves is a key objective in quantum optics. To this end, one often utilizes hybrid structures comprised of elements with different optical properties in order to achieve features such as high R or high A for incident light. A desirable goal would be the possibility to tune between all three regimes of nearly perfect reflection, absorption, and transmission within the same device, thus swapping between the cases R → 1, A → 1, and T → 1 dynamically...
December 5, 2016: Scientific Reports
https://www.readbyqxmd.com/read/27917528/the-ultimate-signal-to-noise-ratio-in-realistic-body-models
#8
Bastien Guérin, Jorge F Villena, Athanasios G Polimeridis, Elfar Adalsteinsson, Luca Daniel, Jacob K White, Lawrence L Wald
PURPOSE: We compute the ultimate signal-to-noise ratio (uSNR) and G-factor (uGF) in a realistic head model from 0.5 to 21 Tesla. METHODS: We excite the head model and a uniform sphere with a large number of electric and magnetic dipoles placed at 3 cm from the object. The resulting electromagnetic fields are computed using an ultrafast volume integral solver, which are used as basis functions for the uSNR and uGF computations. RESULTS: Our generalized uSNR calculation shows good convergence in the sphere and the head and is in close agreement with the dyadic Green's function approach in the uniform sphere...
December 4, 2016: Magnetic Resonance in Medicine: Official Journal of the Society of Magnetic Resonance in Medicine
https://www.readbyqxmd.com/read/27917252/separation-of-superparamagnetic-particles-through-ratcheted-brownian-motion-and-periodically-switching-magnetic-fields
#9
Fan Liu, Li Jiang, Huei Ming Tan, Ashutosh Yadav, Preetika Biswas, Johan R C van der Maarel, Christian A Nijhuis, Jeroen A van Kan
Brownian ratchet based particle separation systems for application in lab on chip devices have drawn interest and are subject to ongoing theoretical and experimental investigations. We demonstrate a compact microfluidic particle separation chip, which implements an extended on-off Brownian ratchet scheme that actively separates and sorts particles using periodically switching magnetic fields, asymmetric sawtooth channel sidewalls, and Brownian motion. The microfluidic chip was made with Polydimethylsiloxane (PDMS) soft lithography of SU-8 molds, which in turn was fabricated using Proton Beam Writing...
November 2016: Biomicrofluidics
https://www.readbyqxmd.com/read/27916948/a-robust-and-device-free-system-for-the-recognition-and-classification-of-elderly-activities
#10
Fangmin Li, Mohammed Abdulaziz Aide Al-Qaness, Yong Zhang, Bihai Zhao, Xidao Luan
Human activity recognition, tracking and classification is an essential trend in assisted living systems that can help support elderly people with their daily activities. Traditional activity recognition approaches depend on vision-based or sensor-based techniques. Nowadays, a novel promising technique has obtained more attention, namely device-free human activity recognition that neither requires the target object to wear or carry a device nor install cameras in a perceived area. The device-free technique for activity recognition uses only the signals of common wireless local area network (WLAN) devices available everywhere...
December 1, 2016: Sensors
https://www.readbyqxmd.com/read/27914775/assessment-of-background-gamma-radiation-levels-using-airborne-gamma-ray-spectrometer-data-over-uranium-deposits-cuddapah-basin-india-a-comparative-study-of-dose-rates-estimated-by-agrs-and-pgrs
#11
D Srinivas, V Ramesh Babu, I Patra, Shailesh Tripathi, M S Ramayya, A K Chaturvedi
The Atomic Minerals Directorate for Exploration and Research (AMD) has conducted high-resolution airborne gamma ray spectrometer (AGRS), magnetometer and time domain electromagnetic (TDEM) surveys for uranium exploration, along the northern margins of Cuddapah Basin. The survey area includes well known uranium deposits such as Lambapur-Peddagattu, Chitrial and Koppunuru. The AGRS data collected for uranium exploration is utilised for estimating the average absorbed rates in air due to radio-elemental (potassium in %, uranium and thorium in ppm) distribution over these known deposit areas...
November 30, 2016: Journal of Environmental Radioactivity
https://www.readbyqxmd.com/read/27914448/a-fractional-calculus-model-of-anomalous-dispersion-of-acoustic-waves
#12
Andrew W Wharmby
An empirical formula based on viscoelastic analysis techniques that employs concepts from the fractional calculus that was used to model the dielectric behavior of materials exposed to oscillating electromagnetic fields in the radiofrequency, terahertz, and infrared bands. This work adapts and applies the formula to model viscoelastic behavior of materials that show an apparent increase of phase velocity of vibration with an increase in frequency, otherwise known as anomalous dispersion. A fractional order wave equation is derived through the application of the classic elastic-viscoelastic correspondence principle whose analytical solution is used to describe absorption and dispersion of acoustic waves in the viscoelastic material displaying anomalous dispersion in a specific frequency range...
September 2016: Journal of the Acoustical Society of America
https://www.readbyqxmd.com/read/27913334/switchable-and-tunable-baw-duplexer-based-on-ferroelectric-material
#13
Almonir Abdulgader Mansour, Thottam S Kalkur
A switchable and tunable bulk acoustic wave (BAW) duplexer for RF applications is presented in this paper. The fabricated BAW duplexer was built on sapphire substrate using solidly mounted resonators. A metal-organic solution deposition technique was used to form resonators with barium strontium titanate (BST) thin film and six layers of silicon dioxide and tantalum oxide as Bragg reflector. By applying dc bias, the BST thin film shows an electrostrictive effect, and the two filter paths of the BAW duplexer switch to a bandpass response with center frequencies at 4...
December 2016: IEEE Transactions on Ultrasonics, Ferroelectrics, and Frequency Control
https://www.readbyqxmd.com/read/27913332/a-method-for-accurate-modeling-of-baw-filters-at-high-power-levels
#14
Andreas Tag, Vikrant Chauhan, Christian Huck, Bernhard Bader, Dominik Karolewski, F Maximilian Pitschi, Robert Weigel, Amelie Hagelauer
A novel approach for multiphysics modeling of bulk acoustic wave (BAW) filters is presented allowing accurate and at the same time efficient modeling of BAW filters at high power levels. The approach takes the different types of losses and their spatial distribution into account in order to provide the required input for thermal simulation. The temperature distribution determined by thermal simulation is used to modify the geometry and the layer stack of each single resonator of the filter. In this way, the required input for modeling of electromagnetic (EM) and acoustic behavior at high power level is generated...
December 2016: IEEE Transactions on Ultrasonics, Ferroelectrics, and Frequency Control
https://www.readbyqxmd.com/read/27911950/a-specialized-multi-transmit-head-coil-for-high-resolution-fmri-of-the-human-visual-cortex-at-7t
#15
Shubharthi Sengupta, Alard Roebroeck, Valentin G Kemper, Benedikt A Poser, Jan Zimmermann, Rainer Goebel, Gregor Adriany
PURPOSE: To design, construct and validate radiofrequency (RF) transmit and receive phased array coils for high-resolution visual cortex imaging at 7 Tesla. METHODS: A 4 channel transmit and 16 channel receive array was constructed on a conformal polycarbonate former. Transmit field efficiency and homogeneity were simulated and validated, along with the Specific Absorption Rate, using [Formula: see text] mapping techniques and electromagnetic simulations. Receiver signal-to-noise ratio (SNR), temporal SNR (tSNR) across EPI time series, g-factors for accelerated imaging and noise correlations were evaluated and compared with a commercial 32 channel whole head coil...
2016: PloS One
https://www.readbyqxmd.com/read/27911555/electromagnetic-signatures-of-the-chiral-anomaly-in-weyl-semimetals
#16
Edwin Barnes, J J Heremans, Djordje Minic
Weyl semimetals are predicted to realize the three-dimensional axial anomaly first discussed in particle physics. The anomaly leads to unusual transport phenomena such as the chiral magnetic effect in which an applied magnetic field induces a current parallel to the field. Here we investigate diagnostics of the axial anomaly based on the fundamental equations of axion electrodynamics. We find that materials with Weyl nodes of opposite chirality and finite energy separation immersed in a uniform magnetic field exhibit an anomaly-induced oscillatory magnetic field with a period set by the chemical potential difference of the nodes...
November 18, 2016: Physical Review Letters
https://www.readbyqxmd.com/read/27911529/emergent-electromagnetic-induction-and-adiabatic-charge-pumping-in-noncentrosymmetric-weyl-semimetals
#17
Hiroaki Ishizuka, Tomoya Hayata, Masahito Ueda, Naoto Nagaosa
The photovoltaic effect due to the adiabatic quantum phase in noncentrosymmetric Weyl semimetals is studied. We particularly focus on the case in which an external ac electric field is applied. By considering a generalized Weyl Hamiltonian with nonlinear terms, we show that the photocurrent is induced by circularly, rather than linearly, polarized light. This photovoltaic current can be understood as an emergent electromagnetic induction in momentum space; the Weyl node is a magnetic monopole in momentum space, the circular motion of which induces the electric field...
November 18, 2016: Physical Review Letters
https://www.readbyqxmd.com/read/27911519/nonclassicality-criteria-in-multiport-interferometry
#18
L Rigovacca, C Di Franco, B J Metcalf, I A Walmsley, M S Kim
Interference lies at the heart of the behavior of classical and quantum light. It is thus crucial to understand the boundaries between which interference patterns can be explained by a classical electromagnetic description of light and which, on the other hand, can only be understood with a proper quantum mechanical approach. While the case of two-mode interference has received a lot of attention, the multimode case has not yet been fully explored. Here we study a general scenario of intensity interferometry: we derive a bound on the average correlations between pairs of output intensities for the classical wavelike model of light, and we show how it can be violated in a quantum framework...
November 18, 2016: Physical Review Letters
https://www.readbyqxmd.com/read/27911366/a-multimodal-imaging-and-stimulation-based-method-of-evaluating-connectivity-related-brain-excitability-in-patients-with-epilepsy
#19
Mouhsin M Shafi, Susan Whitfield-Gabrieli, Catherine J Chu, Alvaro Pascual-Leone, Bernard S Chang
Resting-state functional connectivity MRI (rs-fcMRI) is a technique that identifies connectivity between different brain regions based on correlations over time in the blood-oxygenation level dependent signal. rs-fcMRI has been applied extensively to identify abnormalities in brain connectivity in different neurologic and psychiatric diseases. However, the relationship among rs-fcMRI connectivity abnormalities, brain electrophysiology and disease state is unknown, in part because the causal significance of alterations in functional connectivity in disease pathophysiology has not been established...
November 13, 2016: Journal of Visualized Experiments: JoVE
https://www.readbyqxmd.com/read/27910988/visible-light-controlled-catalytic-cu2o-au-micromotors
#20
Dekai Zhou, Yuguang C Li, Pengtao Xu, Nicholas S McCool, Longqiu Li, Wei Wang, Thomas E Mallouk
Visible light driven Cu2O-Au micromotors exhibit rapid on/off switching and speed control. Electrochemical measurements confirm that the light-induced movement of the Cu2O-Au micromotors involves a self-electrophoresis mechanism modulated by the photoconductivity of Cu2O. This study extends the utilization of the electromagnetic spectrum for micro/nanomotors into the visible range.
December 2, 2016: Nanoscale
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